Degenerative myopia is a significant cause of world blindness and visual disability. It is said to be the seventh ranking cause of legal blindness in the United States of America, while being the fourth ranking cause in Hong Kong. Overall, blindness most commonly occurs from myopic macular degeneration, retinal detachment, cataract and glaucoma, and of these, myopic macular degeneration is the most important. There is no universally accepted treatment to prevent the condition. It is thought to be due to decompensation of the nerve and supporting tissues of the part of the retina of the eye, the macular, which is used for fine vision. One cause of the damage is the axial overgrowth of the eye during the regular growth phase, followed by further increments of stretching during the adult years. By middle age, stressed eye tissues begin to show degeneration and failure of function; crucially, this includes the delicate nerves of the retina.
A scleral reinforcement procedure has been employed for some 50 years in an attempt to prevent macular degeneration. The concept is to graft a strengthening layer of donor or autologous tissue over the weak scleral shell of the eye to reinforce it. This has been found to have limited success, especially in adult eyes. Surgical fabrics have been used in a few studies but with no accepted success. One example of a device of this type is taught in U.S. Pat. No. 6,126,687, issued Oct. 3, 2000 to Peyman. This patent teaches the use of a strip of mesh-like material to apply pressure to the posterior portion of the eye as a treatment for age-related macular degeneration. Many surgeons have found such mesh-like materials difficult to use, in that the suturing of the mesh fabric material creates gathering, folds, pulls and creases in the fabric that are problematic. Thus, surgeons have generally reverted to the use of bands of donor sclera for the reinforcement of the distensible scleral wall of the eye. These grafts take the form of a strip of donor sclera tissue placed over the posterior part of the eye and secured by sutures to the outer coat of the eye to be treated to retard growth and stretching.
Scleral buckling is a related common surgical technique used by ophthalmologists in the repair of retinal detachments. Buckles, made usually of silicone rubber, are sutured to the wall of the eye in such a way as to produce an indentation, so approximating the wall of the eye to an underlying detached retina.